Exercise differences

Hi there

in lockdown my friend and I have been going for a walk each Sunday morning.

we both have Apple watches & track our walks.

we have noticed that the exercise minutes I achieve from doing the exact same walk, pace etc is significantly less. For example today’s walk was just over 8km. She did 89 minutes of exercise whilst mine tracked as 8 minutes. This is a similar result I get for each walk I do.

I assume this could be settings related. Any ideas?